AAPM comments at the Federal Coordinating Council for Comparative Effectiveness Research Listening Session on May 13, 2009.

June 11, 2009

This statement is being given on behalf of the American Association of
Physicists in Medicine (AAPM), which represents over 6,700 medical physicists.
AAPM’s mission is to advance the practice of physics in medicine and biology
by encouraging innovative research and development, disseminating scientific
and technical information, fostering the education and professional development
of medical physicists, and promoting the highest quality medical services for
patients. Medical physicists contribute to the effectiveness of radiological
imaging procedures by assuring radiation safety and helping to develop
improved imaging techniques (e.g., mammography, computed tomography,
magnetic resonance imaging, ultrasound). Medical physicists contribute to the
development of therapeutic techniques (e.g., prostate implants, stereotactic
radiosurgery), collaborate with radiation oncologists to design treatment plans,
and monitor equipment and procedures to insure that cancer patients receive
the prescribed dose of radiation to the correct location.

The Department of Health and Human Services states that: “Comparative
effectiveness research provides information on the relative strengths and
weakness of various medical interventions.” Various alternative medical
procedures and/or technologies may be capable of achieving a given medical
intervention. Thus, it is necessary to compare these medical procedures for
specific groups of patients to optimize the benefit (e.g., earlier detection of
cancer in screening procedures; improved targeted dose delivery in radiation
therapy) and minimize the cost and/or risk (e.g., reduced radiation dose in
diagnostic procedures; minimization of dose to normal tissues and critical
organs in therapeutic procedures). Means to perform such comparative
assessment studies may include clinical evidence-based outcomes evaluations
that require expensive and sometimes lengthy clinical trials involving a
substantial number of patients to achieve statistical certainty. However, when
well-defined physical or engineering differences exist between products, which
do not rely on different anatomic or physiological phenomenon, comparative
effectiveness can be determined by assessing technology using quantitative
metrics. This will be particularly useful and cost effective in situations where
simple modifications of an existing medical technology are introduced or a new
technology is available that is changing rapidly in its potential for proving
efficacy. In those cases and at those times, relatively inexpensive physical
measurements or observer-based diagnostic accuracy studies may be most
appropriate.

Examples of ongoing and future roles of medical physics in comparative
effectiveness studies include optimization of radiation dose in computed
tomography (CT). Image quality can be assessed quantitatively between
different computed tomography (CT) scanners at the same radiation dose
levels, providing an objective measure of comparative effectiveness that may
not require a clinical trial. Another example is the comparative evaluation of
mammography, breast CT, and breast tomosynthesis in detecting and
assessing the extent of breast cancer by using various metrics of physical and
psychophysical image quality (e.g., spatial resolution, noise, or conspicuity) and
balanceing the results in terms of cost and radiation dose level. Another
example is the comparative effectiveness of photon therapy versus proton
therapy in the treatment of prostate cancer by measuring the dose to the tumor
target compared to the rest of the patient’s (normal) tissues. In all these
situations, comparative effectiveness can be ascertained without “costly” clinical
trials, or in advance of such trials.

It is important to note that comparative effectiveness studies are necessary in
diagnostic exams (e.g., screening, detection, diagnosis, risk assessment), as
well as in therapeutic procedures (e.g., response to therapy, radiation treatment
planning). Medical physicists collaborate with other medical professionals and
are integral to the development, evaluation, and implementation of technology
and procedures in medical imaging and in the therapeutic use of radiation.
These activities provide a basis for objective comparative effectiveness for the
underlying technology in medical procedures.

In summary, it is important to realize that technology assessment studies are a
subset of comparative effectiveness studies, that the reach of comparative
effectiveness includes both diagnostic and therapeutic procedures and systems,
and that medical physicists play a vital role in conducting such studies.

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